That must be an error on samsungs site, it very definitely does have wifi
http://www.gsmarena.c...msung_i5500b-3371.php
I get 500MB a month free data allowance and then after that it's a maximum of £1 a day for data, I've never gone over the 500MB though (although I don't use it much for internet as such)... Though, obviously things like that are dependent on the SIM that's in the phone, not the phone itself.
Yes you can access the internet without using the wifi, how fast the connection would be is dependent on what signal you have in whatever location you are in, but it does support 3g, so as long as you have a 3g signal you can get uptp 7.2Mb/s
If you want flash then you are limited to phones with a 1Ghz or faster CPU, it won't run on anything less than that.